Caking bomb assembly



Sept. 11, 1956 BARNES ET AL 2,762,294

CAKING BOMB ASSEMBLY Filed Aug. 8, 1951 2 Sheets-Sheet 1 Mar/0n Z7.Barnes L/O/WSJ L ed INVENTORS ATTORNEY Sept. 11, 1956 BARNES ET AL2,762,294

CAKING BOMB ASSEMBLY Filed Aug. 8, 1951 2 sneet s-sneet 2 Mar/0n l7.Bar/79.5

dame; P. L e0 INVENFORS By 02% #wm ATTO/TNf) United States Patent CAKINGBOMB ASSEMBLY Marion 1). Barnes and James P. Lea, El Dorado, Ark., as-

signors, by mesne assignments, to Monsanto Chemical Company, St. Louis,Mo., a corporation of Delaware Application August 8, 1951, Serial No.240,942

2 Claims. (Cl. 100--99) This invention relates to a caking combassembly, and more particularly to an apparatus for simultaneouslypreparing a plurality of specimens in the form of compressed cakes.

Considerable effort has been made in the fertilizer industry to minimizethe tendency of fertilizers to cake. While much progress has been madealong this line, the caking problem still exists. For instance, ammoniumnitrate is manufactured in the form of pellets and the pellets coated inorder to reduce caking. In view of the foregoing, as a control measure,it is necessary to provide means for preparing a large number ofspecimens for making caking tests. Accordingly, the present inventionrelates to an apparatus for preparing such specimens.

Our copending applications Serial Nos. 547,254 and 547,255, each filedNovember 14, 1955, constitute divisions of the present application.

2,762,294 Patented Sept. 11, 1956 The entire assembly of bombs in therack is placed in a cabinet (not shown) and the ammonium nitrate is subjected to controlled conditions as to pressure, temperature and humidityfor about one week. The ammonium nitrate cakes formed are removed fromthe bombs'by loos ening the jack screws 10, removing the cake-formingcups 21 and 22 from between the jack screws and the bellows, andremoving the cakes of nitrate therefrom. The ten-' dency of the ammoniumnitrate to cake is then determined by measuring the pressure required tocrush the thus formed cakes, e. g. in a Carver laboratory press.

Referring in more detail to Figures 1 and 2 of the drawings it will beseen that our caking bomb assembly comprises a rigid frame having a topmember 11, a spaced bottom member 11, and connecting side members. Aseries of pressure-responsive metallic bellows 3 depend from the topmember 11 of the rack 1 in alignment each with one of the jack screws1-0 disposed on the bottom member 11 of the rack. Each of the cylinderassemblies 2 is comprised of a bearing plate 20 which sets over the baseplate 11 of the rack 1 as shown, and eliminates a tendency of the cupsto turn as the jack screw is turned.

comprises an unsplit cylinder.

Although not limited to such application, the invention i Eachsuperimposed bomb assembly is made up of the following components asshown in detail in Figure 2. A base plate 24 rests on the bearing plate20 and a cakeforming cup 23 sets on the base plate 24. Each cup 23 Thetop plates 25 are provided to be inserted in the cylinders 23 on top ofthe nitrate pellets disposed therein. A follower plate 26 rests atop thetop plate 25. The second superimposed cylinder assembly is identicalwith that described with the exception that the bellows 3 rests incontact with the top plate 25 i rather than a second follower plate 26.

Except for the cup plates 25, preferably the other parts of the cylinderassembly are made'of transparent material such as Lucite so that theoperator can determine at a glance the progress of thecake-forming'operation; T00,

This invention will be understood more readily from the followingdescription of apparatus.

Referring to the drawings generally:

Figure 1 is a side elevation, partly in section, of a caking bomb andassembly rack according to the present invention.

Figure 2 is an exploded isometric view showing the parts of the bombunit of Figure l disassembled.

Figure 3 is a side elevation showing the weighted lever arrangement forapplying constant pressure to the material disposed in the caking bombassemblies of Figure 1.

Figure 4 is a plan view on line 44 of Figure 3.

Referring to the drawings in greater detail, numeral 1 generallydesignates a rack or frame adapted to accommodate any desired number ofbomb assemblies represented generally by the numeral 2. Each bomb unitcomprises metallic double wall bellows 3 depending from top member 11 ofrack 1. A head 4, held in the opening 5 (Figures 1 and 2) of the rackwith cotter pins 6 cornmunicates with the bellows through a tappedopening 7 into which a pressure gauge 8 is threaded. The bellows arefilled with a fluid such as an organic fluid (e. g. mineral oil, dibutylphthalate), water, or air in order to transmit the pressure to thegauge, which may be initially applied to the cakes 9 by tightening thejack screw 10, threaded into the base plate 11 of the rack. Thematerial, e. g. ammonium nitrate pellets 18, to be pressed is placed inthe cups 21 and 22 and the plates 25 laid on top of the ma terial. Asindicated above, the desired pressure on the ammonium nitrate pelletsmay be initially applied by tightening the jack screws 10.

the cake is easier to remove from plastic cups than from metal cupsbecause of less tendency of cakes to stick to plastic cups. Desirably,the top plates 25 are of metal or other adequately rigid material inorder to enable the application of uniform pressure to the materialbeing pressed. The greater the thickness of the upper'plates, thegreater the tendency for them to tilt laterally out of alignment andbind against the inside walls of the cylinders 23, which causes unevenpressure and uneven formation of cake. The use of transparent cylindersalso on ables the operator to readily detect any such binding that mayoccur and relieve same.

Increasing the capacity of a given bomb assembly by superimposing inthis manner is quite significant in that conservation of space in thetemperature-humidity control cabinet is very important; it alsomaterially reduces the man hours required in loading, unloarding andhandling the specimens, and of course, materially reduces the cost ofpreparing the caked specimens.

In connection with the preparation of the test samples in thetemperature-humidity control cabinet, it was found in most cases thatduring the first day of the cake-forming operation the ammonium nitratewould settle, thereby causing a decrease in volume and a correspondingdrop in pressure. In order to maintain a reasonably constant pressure,this makes it necessary for the operator to check the bombs periodicallyand compensate for the pressure drop by tightening the jack screws 10.

To obviate this difiiculty we have found, in accordance with the presentinvention, that a constant pressure may be maintained upon the samplesduring their time in the temperature-humidity cabinet by the use of aweighted lever system 35 of the type shown in Figures 3 and 4. Only onelever system, and preferably only one pressure gauge, are needed in theentire assembly. The lever sys- 3 tern shown includes a lever arm 36pivoted about a pin 37 passing therethrough and through one end of aplate 38 fixedly attached at its opposite end to the rack 1, one or moreweights 39 suspended from the lever arm, and adjustable at variouspoints along its length, and a tapered metal rod 40.

The extra bellows 3 associates with the lever system 35, communicateswith the depending bellows in contact with the bomb assemblies by meansof a pressure system 27 comprising the main fluid supply line 28 and theTs 30 which deliver fluid from the supply line 28 to the individualbellows 3 through the medium of the flare type adapters 33.

Where the lever system is used to maintain the pressure constant, onlyone pressure gauge 8 need be used in the fluid supply system as shown inFigure 3. A T 31 may be used for connecting the pressure gauge to themain pressure line 28.

It has been found that using a 10 preset from the horizontal on thelever arm as shown minimizes any tendency for the tapered rod to movelaterally as the lever swings an arc. Likewise it has been found thatusing a 60 tapered rod 40 and a 120 V-notch 41 in the lever arm allowsthe lever arm to swing through its are without binding, due to theknife-edge rocking elfect, and also minimizes lateral shift of thetapered rod. By minimizing lateral shift and binding, the need ofemploying a double linkage and guide arrangement on the lever system iseliminated. Although these particular conditions as to degree preset ofthe lever arm, angle of the V-notch and taper of said rod have beenfound to give very good results, such conditions are not critical andvariations therein are satisfactory.

The lever system, in conjunction with the fluid-filled bellows andjackscrews 10, serve exceptionally well the dual function ofsimultaneously applyingpressure and stabilizing it. Once the desiredpressure is reached on the cylinder assemblies the lever system shownand described has proven an excellent means for maintaining the pressureconstant.

As many apparent widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsdisclosed except as defined in the appended claims.

We claim: a

1. Apparatus for simultaneously preparing a plurality of test samples ofgranular material under simulated conditions of storage tending to causesaid material to coalesce comprising a rigid frame, said frame having atop member, a spaced bottom member and connecting side members, a seriesof pressure responsive metallic bellows depending from said top member,means for mounting a series of superimposed cylinders on said bottommember so as to be in alignment each with a free end of one of saiddepending bellows, each of said cylinder mounting means comprising anunattached bottom plate supported upon said bottom member of said frame,a cylinder for holding a sample of said granular material resting uponsaid bottom plate, a closure disk of less diameter than said cylinder tobe inserted therein on top of said granular material, a follower disk ofless diameter than said closure disk resting thereupon, a second bottomplate resting upon said follower disk, at second cylinder resting uponsaid second bottom plate for holding a second sample of said granularmaterial, a second closure disk of less diameter than said secondcylinder to be inserted therein on top of said granular material, afluid supply system communicating with each of said bellows for applyingpressure to the samples of granular material disposed in saidsuperimposed cylinders, the top most cylinder closure disk of each ofsaid cylinder mounts having contact with the free end of one of saiddepending bellows in alignment therewith upon the application ofpressure to said samples, pressure indicating means whereby the pressureon said samples may be observed, and a weighted lever system forautomatically compensating for drops in pressure on said samples due tothe gradual coalescence of said granular material during prolongedexposure thereof to other simulated conditions such as temperature andhumidity to which said material is likely to be subjected in storage.

2. Apparatus for simultaneously preparing a plurality of test samples ofgranular material under simulated conditions of storage tending to causesaid material to coalesce comprising a rigid frame, said frame having atop member, a spaced bottom member and connecting side members, a seriesof pressure responsive unconfined bellows depending from said topmember, a series of cylinder assemblies for holding samples of saidgranular material mounted upon said bottom member each in alignment withone of said depending bellows, a fluid supply system communicating witheach of said bellows, pressure indicating means connected to said fluidsupply system, an additional fluid-filled pressure responsive bellowsfor delivering fluid under pressure to said system communicating withsaid other depending bellows, a tapered pin on one end of saidadditional bellows, a pivoted lever arm having one end thereof notchedfor contact with the pin of said bellows, an adjustable weight on theother free end of said lever arm whereby pressure may be automaticallyapplied to said samples of material dispgsed in said cylinder assembliesand maintained constant over a prolonged period while said samples aresubjected to simulated temperature and humidity conditions likely to beencountered in the storage thereof, the free ends of said dependingbellows having contact with said cylinder assemblies in alignmenttherewith upon the application of pressure to said samples.

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